How Do Twitter Users React to TV Broadcasts Dedicated to Vaccines in Italy?

"[D]iscussion on social media in reaction to public events is rich and could be used to inform communication initiatives for vaccine promotion."

Messages on vaccines transmitted by traditional media often elicit a reaction on social media; therefore, monitoring social media in reaction to news transmitted by traditional media can provide a source of information on vaccine confidence. This study analysed the sentiment of tweets published in reaction to two TV broadcasts in Italy dedicated to vaccines, one based on scientific evidence [Presa Diretta (PD)] and one including anti-vaccine personalities [Virus (VS)].

Both broadcasts were aired on prime time on the Italian public TV and were conducted by a presenter. PD, which aired on prime time TV on January 10 2016 and was viewed by an audience of 1,690,000, addressed fears and misconceptions about vaccinations through communicating evidence-based information on vaccines through previously recorded videos of experts in the field. VS was a talk show hosting a discussion between pro-vaccine persons and two vaccine-hesitant personalities (an actress and a music critic). Broadcast on May 12 2016, VS had an audience of 1,252,000.

For the study, Tweets about vaccines published in an 8-day period centred on each of the two TV broadcasts were classified by sentiment (based on the tweets' text; links to external resources were not evaluated). Twitter data were extracted from the database of the VCMP platform, a system monitoring vaccine confidence in Italy based on web data. The researchers downloaded 12,180 tweets pertinent to vaccines, published by 5,447 users; 276 users tweeted during both broadcasts.

Sentiment was positive in 50.4% of tweets, negative in 37.7%, and neutral in 10.1% (remaining tweets were unclear or raised questions). The positive/negative ratio was higher for VS compared to PD (6.96 vs. 4.24, P<0.001). Positive sentiment was associated with the user's number of followers (odds ratio (OR) 1.68, P<0.001), friends (OR 1.83, P<0.001), and published tweets (OR 1.46, P<0.001) and with being a recurrent user (OR 3.26, P<0.001). This observation suggests that active users could spread information on vaccines to a large audience.

The frequency of vaccine-related tweets after both broadcasts was higher compared to tweets published before the broadcast airing, confirming that TV programmes can trigger an intense discourse among Twitter users. Sentiment was mainly positive, especially among very active users. Despite the prevalence of vaccine-hesitant issues emerging during VS, the positive/negative ratio increased after the airing of VS, suggesting that anti-vax messages in TV broadcasts do not necessarily elicit negative opinions on vaccines on Twitter. This confirms the observation that the effect of communication on vaccines and other health issues is not straightforward. Therefore, according to the researchers, the determinants of the effect of different vaccine communication initiatives on vaccine confidence should be investigated at the local level and in specific population sub-groups, as such effect is likely affected by specific characteristics of both the message and the intended audience.

In conclusion: "The information acquired through social media monitoring can be used to inform public health communication campaigns, as it can facilitate a better understanding of a specific though relevant subgroup of the population (social media users), both in terms of community structure and in terms of shared contents (interests and concerns). This kind of information can be useful to plan real-time responses to doubts and misconceptions emerging during the TV broadcasts, but also as a knowledge basis to plan - and monitor - vaccine promotion campaigns in the long term."